1. Field of the Invention
The invention relates to tufted carpeting material, particularly carpeting material useful as an entry mat to remove dirt and water from shoes.
2. Background Art
Various devices have been employed at the entryways of buildings to reduce or remove the accumulation of various solid materials (hereinafter referred to merely as "dirt") and water typically found on the shoe soles and other pedestrian surface contacting parts of the shoe such as the heel (all of such parts hereinafter being referred to as the "shoe soles") of persons entering the building. Such devices typically include a mat which provides a brushing or wiping action against the shoe sole.
Such mats are generally fibrous or fabric in nature to provide the desired frictional surface and wiping action. Most fabrics or fibrous mats are not, however, completely satisfactory because they have a very limited capacity for storage of removed dirt and water and most are not particularly conducive to the rapid evaporation of water. They require frequent shaking and washing to rejuvenate the mats for subsequent uses.
Attempts have been made to provide floor mats which have a greater capacity for the storage of accumulated dirt, but these have generally been somewhat less than satisfactory. For example, lengths of solid materials such as edgewise oriented pieces of metal or segments of cut up automobile tires have been linked together, leaving spaces therebetween, to provide for the storage of dirt and other debris. Such mats, however, are not satisfactory because, besides being poor water absorbers, they leave the dirt removed plainly in view and they also require that the dirt be collected and removed after the mat is displaced since such mats generally have no bottom layer.
Some fabric or fibrous mats are unattractive and/or fail to provide a luxuriant underfoot surface. The more attractive and luxuriant mats are generally formed of very dense carpet pile, providing a surface with only a limited capacity for the storage of dirt and a structure from which water will be evaporated slowly.
Such carpet mats typically consist of a heavy backing attached to keep the mat in place upon which are deployed tufted fibers typically on the order of 6 to 15 denier per filament, a common fiber size for conventional carpeting material. While these fibers look good and have a pleasing texture when used in carpet, a mat of such conventional carpet fibers presents a rather closed surface which has little if any space to store and conceal dirt. Such a shortcoming gives rise to a phenomenon known in the entryway mat business as "retracking".
Retracking occurs when removed dirt on the surface of a mat such as tufted carpet with insufficient dirt storage space remains on the top of the mat and is picked up by the next person walking over the mat, causing the dirt to move further along on the mat until it is eventually carried into the building.
While mats containing larger denier fibers, such as those formed of coir (sometimes called "coco") fibers, fibrillated polypropylene film or large denier vinyl fibers, provide a sufficiently open mat to store dirt between such fibers, the large denier fibers are not very effective in absorbing and evaporating water.
U.S. Pat. No. 4,045,605 (Breens et al) discloses a carpeting material which includes pile or tuft fibers comprising 75 to 98% by weight of conventional carpet fibers and 2 to 25% by weight of stiff fibers or filaments arranged, not to provide openness to store removed dirt, but to act as dirt scrapers. The stiff fibers are not crimped. The conventional carpet fibers are less than 30 decitex per filament (about 27 denier) while the stiff fibers or filaments are of from 30 to 300 tex (about 270 to about 2700 denier). (The term "denier" refers to the weight in grams for a 9,000 meter fiber while the term "tex" refers to the weight in grams for a 1,000 meter fiber. Decitex is one-tenth of tex. A 0.11 tex fiber, or 1.1 decitex fiber would be 1 denier.) While Breens et al indicate that the stiff fibers may be fed in with each row of conventional pile or tuft yarn or in alternate rows or less frequently, using a conventional tufting machine or carpet loom, Breens et al also contemplate one or more rows of tufts of conventional carpet yarn followed by a row of stiff fibers or filament. Such an arrangement would not provide sufficient openness for the storage of removed dirt.